# Q: Is 1 a Perfect Square?

A: Yes, the number 1 is a perfect square.

## Why is 1 a perfect square?

A perfect square is a number that can be expressed as the product of two equal integers.

The only way to accurately calculate if a number is a perfect square is to find the factors. Before we go through the trouble of finding the factors, there is a quick trick you can use to help determine if you need even need to do the extra work.

Try these steps first:

1. A number that is a perfect square never ends in 2, 3, 7 or 8. If your number ends in any of those numbers, you can stop here because your number is not a perfect square.
2. Obtain the digital root of the number. The digital root essentially is the sum of all of the digits. If you're lost, don't worry, we'll go over each step in more detail below.
3. All possible numbers that are a perfect square have a digital root of 1, 4, 7, 9.

Let's try it...

Step 1:

What is the last number of 1? It is this number: 1. The answer is 1. Is 1 in the list of numbers that are never perfect squares (2, 3, 7 or 8)?

Answer: NO, 1 is not in the list of numbers that are never perfect squares. Let's continue to the next step.

Step 2:

We now need to obtain the digital root of the number. Here's how you do it:

1. Split the number up and add each digit together:

1 = 1

What is the digital root of number 1?

Step 3:

So now we know the digital root of 1 is 1. Is 1 in the list of digital roots that are always a square root (1, 4, 7 or 9)?

Answer: YES, 1 is in the list of digital roots that are always perfect squares. We can conclude that 1 could be a perfect square!

Factoring

OK, so now we know that 1 could be a perfect square. We have to find the factors of the number to be sure.

Here are all of the factors of 1:

1 x 1

Highlighted in orange above is the factor combination that makes 1 a perfect square. Do you see why? A number can only be a perfect square if the product of two exactly the same numbers is equal to the original number.

Here's the proof: 1 x 1 = 1

### More Examples

 Number 2 3 4 Perfect Square? no no yes

### Explore more about the number 1:

General Questions
Factoring Questions
Calculation Questions
Miscellaneous Questions